A pinion having 20° full depth involute profile has 19 tooth and the meshing gear has 37 tooth. If the module is 5 mm, the center distance between the gear pair will be

Concept:

The center distance between the gear pair is given by:

Centre distance =\(\left( {\frac{{{D_1} + {D_2}}}{2}} \right)\), 

where D1 = Pitch diameter of pinion, D2 = Pitch diameter of the gear

Module:

• The module is the ratio of the pitch diameter of gear to the no of teeth, \(m = \frac{D}{T}\)
• The module of two mating gears must be the same (m1 = m2).

Calculation:

Given:

T1 = 19, T2 = 37, m = 5

For pinion, 

\(m = \frac{{{D_1}}}{{{T_1}}}\)

\( \Rightarrow 5 = \frac{{{D_1}}}{{19}} \Rightarrow {D_1} = 95\;mm\)

For gear, \(m = \frac{{{D_2}}}{{{T_2}}}\)

\( \Rightarrow 5 = \frac{{{D_2}}}{{37}} \Rightarrow {D_2} = 185\)

Center distance \( = \frac{{{D_1} + {D_2}}}{2} = \frac{{95 + 185}}{2} = 140\;mm\)